Screening Of Functionalized Self-assembling Peptides With Angiogenic Activity And Their Cytological Evaluation

The functionalized self-assembling peptide nanofiber scaffolds have become theemerging biomaterials of tissue engineering because of their unique design, goodbiocompatibility and biodegradability. The growth and establish of the microvascularsystem in three-dimensional scaffold is not only an important guarantee for tissueengineering graft to long-term survive, but also one of the bottlenecks of tissueengineered products in the clinical application.In this paper, a series of functionalized self-assembling peptide nanofiber scaffoldswith potential angiogenic activity were designed and prepared. The microstructure ofself-assembling peptides was observed with the methods of material analysis. Thenpeptides with angiogenic activity were screened from the aspect of cytology. To furthervalidate the screened peptides, two-dimensional culture of endothelial cells and smoothmuscle cells was taken to observe the growth condition on the peptide hydrogels.In consideration of promoting endothelial cells adhesion and proliferation andinhibiting their apoptosis, six peptide motifs was designed from the related proteins andgrowth factors. These peptide motifs were grafted in the end of self-assembling peptideRADA16-I by solid phase synthesis. The functionalized peptide solutions were mixedin a volume ratio of1:1with1%pure RADA16-I solution to get1%functionalizedself-assembling peptide mixtures. The typical beta-sheet secondary structure offunctionalized peptide mixtures was confirmed by circular dichroism analysis. Uniformnanofiber structure can be seen in the atomic force microscope (AFM). Under thescanning electron microscope (SEM), uniform porous structure was observed whichwas very similar to the natural extracellular matrix. These results show thefunctionalized peptide nanofiber scaffolds are suitable as three-dimensional tissueengineering scaffolds.Human umbilical vein endothelial cells (HUVEC) were seeded on the surface offunctionalized self-assembling peptide hydrogels. Two functionalized peptide motifsKLT (KLTWQELYQLKYKGI) and PRG (GPRGDSGYRGDS) with potentialangiogenic activity were screened out through the condition of cell adhesion,proliferation, migration and morphology differentiation.To further confirm these two pro-angiogenic peptides, the two-dimensional co-culture of endothelial cells and smooth muscle cells was conducted. These twofunctionalized self-assembling peptide scaffolds promoted cell adhesion, proliferationand morphology differentiation.